THE IMPACT OF CALICEAL PELVIC ANATOMY ON STONE CLEARANCE AFTER SHOCK WAVE LITHOTRIPSY FOR PEDIATRIC LOWER POLE STONES

International Alliance of Urolithiasis (IAU) guidelines on the management of pediatric urolithiasis

The aim of this study was to construct the sixth in a series of guidelines on the treatment of urolithiasis by the International Alliance of Urolithiasis (IAU) that by providing a clinical framework for the management of pediatric patients with urolithiasis based on the best available published literature. All recommendations were summarized following a systematic review and assessment of literature in the PubMed database from January 1952 to December 2023. Each generated recommendation was graded using a modified GRADE methodology. Recommendations are agreed upon by Panel Members following review and discussion of the evidence. Guideline recommendations were developed that addressed the following topics: etiology, risk factors, clinical presentation and symptoms, diagnosis, conservative management, surgical interventions, prevention, and follow-up. Similarities in the treatment of primary stone episodes between children and adults, incorporating conservative management and advancements in technology for less invasive stone removal, are evident. Additionally, preventive strategies aiming to reduce recurrence rates, such as ensuring sufficient fluid intake, establishing well-planned dietary adjustments, and selective use pharmacologic therapies will also result in highly successful outcomes in pediatric stone patients. Depending on the severity of metabolic disorders and also anatomical abnormalities, a careful and close follow-up program should inevitably be planned in each pediatric patient to limit the risk of future recurrence rates.

Contemporary considerations in the management and treatment of lower pole stones

The presence of lower pole stones poses a unique challenge due to the anatomical considerations involved in their management and treatment. Considerable research has been performed to determine the optimal strategy when faced with this highly relevant clinical scenario. Standard options for management include observation, shock wave lithotripsy, retrograde intrarenal surgery, or percutaneous nephrolithotomy. Indeed, each approach confers a distinct set of risks and benefits, which must be placed into the context of patient preference and expected outcomes. The current state of practice reflects a combination of lessons learned from managing calculi not only in the lower pole, but also from other locations within the kidney as well.

Ability of ESWL nomograms to predict stone-free rate in children

INTRODUCTION

We aimed to evaluate whether the pediatric extracorporeal shock wave lithotripsy (ESWL) nomograms can predict stone-free status in children effectively and whether they are applicable to our series. We hypothesize that two current nomograms predicting successful treatment with ESWL in pediatric patients are valid.

STUDY DESIGN

We evaluated 415 renal units (children <18 years) with eligible data who received ESWL treatment for upper urinary tract stones. Children's age, gender, stone size, stone surface area, stone location and history of previous intervention were recorded. Children with no residual fragments after ESWL treatment were designated as stone-free. The nomograms described by Dogan and Onal were implemented to our series for the prediction of stone-free status.

RESULTS

Mean age of children was 64.7 ± 57.2 months. Male to female ratio was 219:196.78.8% (327) of children had single stone. Mean stone size was 10.0 ± 3.7 mm and mean stone surface area was 380.0 ± 72.2 mm². Our stone-free rate after single ESWL session was 52.5% (218/415). Mean residual stone size and stone surface area after single session was 6.4 ± 3.3 mm and 36.0 ± 44.2 mm² respectively. There were no significant difference between stone-free children and children with residual fragments regarding gender, age and history of previous intervention. Mean stone size and stone surface area in stone-free children were lower and lower pole stones had the lowest stone-free rate (p < 0.05). Area under curve for Dogan and Onal nomogram were 0.628 and 0.580 respectively in ROC analysis (0.05). The agreement between Dogan and Onal score was moderate in our series. In multivariate analysis only stone surface area and Dogan score found to be independent predictors of stone-free status (p < 0.05).

DISCUSSION

Only one study has assessed both nomograms in the literature. Both nomograms are reported to be independent predictors of stone free status. ROC analysis in our study revealed fair accuracy for both nomograms with higher area under curve for Dogan nomogram. Higher accuracy for both nomograms were reported by other authors. These nomograms offer practical data but more effective tools are needed to be developed for the prediction of stone-free status in pediatric ESWL.

CONCLUSIONS

Stone size and stone surface area are associated with stone clearance. Dogan and Onal nomograms can be useful in prediction of stone-free status in children. Dogan nomogram is superior to Onal nomogram.

Mini-percutaneous nephrolithotomy versus shock wave lithotripsy for the medium-sized renal stones

INTRODUCTION

The aim of this study was to assess the clinical outcomes of mini-percutaneous nephrolithotomy (Miniperc) and shock wave lithotripsy (SWL) for medium-sized renal stones.

EVIDENCE ACQUISITION

A literature search was performed in February 2020 using the Pubmed, Web of Science and Embase. The outcome measurements between two procedures were stone-free rates (SFR), complication rates, operative time, hospitalization stay time, re-treatment rate, auxiliary procedures rate and efficiency quotient. Results were pooled by Review Manager version 5.3 software.

EVIDENCE SYNTHESIS

Seven studies on 936 patients (N.=471 for SWL and N.=465 for Miniperc) were included. Miniperc was associated with a higher SFR (OR: 0.25; P<0.00001). In addition, we performed a subgroup analyses for pediatric renal stones and lower pole stones, pooled results also favored Miniperc for higher SFR. SWL was associated with higher auxiliary procedure (OR: 3.32; P<0.00001), higher re-treatment rate (OR: 19.19; P<0.00001) and lower EQ (OR: 0.18; P=0.0003) compared with Miniperc. Besides, SWL was associated with a lower complication rate (OR: 0.36; P=0.0001), shorter operative time (WMD: -34.01; P<0.00001), fluoroscopy time (WMD: -134.48; P<0.00001) and hospital time (WMD: -49.11; P<0.00001) compared with Miniperc.

CONCLUSIONS

Miniperc offers a significantly higher SFR, lower auxiliary procedure and re-treatment rate, but SWL was associated with fewer complications.

European Association of Urology and European Society for Paediatric Urology Guidelines on Paediatric Urinary Stone Disease

CONTEXT

Paediatric stone disease is an important clinically entity and management is often challenging. Although it is known that the condition is endemic in some geographic regions of the world, the global incidence is also increasing. Patient age and sex; the number, size, location, and composition of the stone; and the anatomy of the urinary tract are factors that need to be taken into consideration when choosing a treatment modality.

OBJECTIVE

To provide a general insight into the evaluation and management of urolithiasis in the paediatric population in the era of minimally invasive surgery.

EVIDENCE ACQUISITION

A nonsystematic review of the literature on management of paediatric urolithiasis was conducted with the aim of presenting the most suitable treatment modality for different scenarios.

EVIDENCE SYNTHESIS

Because of high recurrence rates, open surgical intervention is not the first option for paediatric stone disease, except for very young patients with very large stones in association with congenital abnormalities. Minimally invasive surgeries have become the first option with the availability of appropriately sized instruments and accumulating experience. Extracorporeal shockwave lithotripsy (SWL) is noninvasive and can be carried out as an outpatient procedure under sedation, and is the initial choice for management of smaller stones. However, for larger stones, SWL has lower stone-free rates and higher retreatment rates, so minimally invasive endourology procedures such as percutaneous nephrolithotomy and retrograde intrarenal surgery are preferred treatment options.

CONCLUSIONS

Contemporary surgical treatment for paediatric urolithiasis typically uses minimally invasive modalities. Open surgery is very rarely indicated.

PATIENT SUMMARY

Cases of urinary stones in children are increasing. Minimally invasive surgery can achieve high stone-free rates with low complication rates. After stone removal, metabolic evaluation is strongly recommended so that medical treatment for any underlying metabolic abnormality can be given. Regular follow-up with imaging such as ultrasound is required because of the high recurrence rates.

Pediatric stone disease: Current management and future concepts

Treatment of pediatric urolithiasis consists of medical and surgical approaches. The main goal of the treatment is to prevent stone recurrence by avoiding multiple surgical interventions. In recent years, many innovations have been reported in the medical diagnostic evaluation protocol and in surgical treatment. According to recent reports, single mutations could be responsible for a larger proportion of renal stones. This etiologic feature holds the potential to change the management in stone prevention from metabolically directed therapy to more specific approaches. In addition, miniaturized instruments have been adopted in clinical practice. In recent years, minimally invasive endoscopic surgery is the treatment of choice in pediatric urolithiasis. This review aims to assess the current literature on medical and surgical treatment options for pediatric urolithiasis. We also aim to provide an overview of potential future advances.

Does Previous Open Stone Surgery Affect the Outcome of Shock Wave Lithotripsy Treatment in Children?

INTRODUCTION

The aim of the study was to evaluate the efficiency of shock wave lithotripsy (SWL) in children who previously underwent ipsilateral open renal stone surgery (ORSS).

METHODS

A total of 315 renal units (RUs) with renal stones underwent SWL treatment in our department over a period of 18 years. A total of 274 RUs (87%) with no history of ORSS were categorized as group 1 and 41 RUs (13%) with a history of ORSS were categorized as group 2. The characteristics of the patients and renal stones, as well as the treatment modalities, were reviewed retrospectively, and the results were compared in terms of the rates of stone-free patients and complications.

RESULTS

The stone-free rates were statistically lower in patients with an existing history of ORSS (p = 0.002), especially for stones located at the lower calyx (p = 0.006). However, there were no differences between groups in the rate of complications (p = 0.75). History of ipsilateral ORSS, age, and stone burden were independent risk factors that predicted a stone-free status in the regression analysis (p = 0.016, p = 0.045, and p = 0.001, respectively).

CONCLUSION

The overall stone-free rate after SWL was found to be significantly lower in children with a history of ORSS than in those without, and this finding was significantly prominent for lower calyx stones. In spite of the possible difficulties in achieving surgical access due to anatomical changes in retrograde intrarenal surgery or mini-/micro-percutaneous nephrolithotomy, we believe that these techniques might be good alternatives for SWL in future cases.

Minimally Invasive Approaches in Pediatric Urolithiasis. The Experience of Two Italian Centers of Pediatric Surgery

Background: Over the last 30 years, the incidence of pediatric urolithiasis (PU) has been increasing and the surgical management has evolved toward a minimally invasive approach (MIA). We reported the experience of two Centers of Pediatric Surgery in the management of PU, focusing on MIA as first choice in treatment. Methods: Data were retrospectively analyzed from October 2009 to October 2019 in children with urolithiasis who were admitted to two referral Italian Centers of Pediatric Surgery. Demographic and clinical data of the patients, features of the urolithiasis, type of surgery were considered. Results: Seventy patients (7.3 ± 5.0 years) with normal renal function were treated for calculi in the pyelocaliceal system (45.7%), ureter (34.3%), bladder (4.3%), urethra (1.4%), and multiple locations (14.3%). Size of calculi was >10 mm in 55.7% of cases (kidney>bladder/urethra>multiple>ureter, p = 0.01). Symptoms were present in 75.7% of patients. Family history was positive in 16.9% of cases. MIA was performed in 59 patients (84.3%): 11.8% shockwave lithotripsy (kidney>ureter>multiple); 32.2% ureteral retrograde surgery (ureteral>other localizations); 30.5% retrograde intrarenal surgery (kidney>other localizations); and 25.4% other procedures including percutaneous nephrolithotomy, cystoscopic bladder stone removal or laser cystolithotripsy (kidney>bladder>multiple). Preoperative stenting was necessary in 52.8% of cases. Four MIA procedures (6.9%, kidney>ureter/multiple) were converted to open surgery. Open surgery was required as first approach in 15.7% of patients (kidney>ureter>multiple) who needed urgent surgery or had associated congenital renal anomalies. In 18/70 of children (25.7%), with prevalence of stones in kidney and multiple location (p < 0.01), a second procedure completed the treatment (88.8% MIA). Intraoperative difficulties were recorded in 8.5% of cases, without difference between location and size of calculi. Late complications (5.7%) were related to displacement and infection of the ureteral stent. Conclusions: MIA resulted to be feasible in more than 75% of primary surgery and in more than 85% of cases requiring a second procedure. Preoperative stent was mandatory in more than 50% of children. The technological evolution allowed to overcome many of the technical difficulties related to the approach to the papilla and lower calyxes. Open surgery is reserved for selected cases and endoscopic surgery represents the best choice of treatment for PU.

Postural therapy for renal stones in children: A Rolling Stones procedure

INTRODUCTION

Despite many advances, the management of renal stones - especially lower caliceal stones (LCS) - remains a challenge. The gravity-dependent location of the lower calices hinders the spontaneous clearance of fragments, which can be a nidus for future growth and symptomatic recurrence. Currently, there is no standard adjunctive therapy to facilitate fragment passage.

OBJECTIVES

To report the safety and effectiveness of mechanical percussion diuresis and inversion (PDI) therapy for eliminating renal stones in children.

PATIENTS AND METHODS

Since November 2013, children with residual fragments (after shock wave lithotripsy or flexible ureteroscopy) or native symptomatic renal stones were prospectively included in a protocol of four PDI sessions. After giving written consent, the children drank 10 ml/kg of water 30 min before therapy. They then laid in a prone Trendelenburg position on a couch angled at 45° and received continuous 10-min mechanical percussion applied over the affected flank by a physiotherapist (Figure summary). Tolerance stone burden reduction and stone clearance were documented with ultrasound 4 weeks after the last session.

RESULTS

Seventeen participants, with a median age of 10.8 years (range 18 months to 18 years), received 82 PDI sessions performed over 22 months. The median stone diameter was 5 mm (range 3-9). All children tolerated the PDI therapy well. Over a median follow-up of 11 months (range 3-18), no significant adverse effects were noted. The overall stone-free rate was 65%. Four of the six patients with residual fragment passed their fragments. The patients who did not become stone free by PDI experienced a decrease in fragment size of 57% (range 34-71). The observance rate was 100%.

DISCUSSION

Many studies have demonstrated that the gravity-dependent position of the lower calyces appears to be an important factor limiting the clearance of LCS. Positioning patients with a degree of inversion in order to put the collecting system beyond the horizontal plane affected the LCS through gravitational force. Complications were rare. PDI appeared to save costs and have similar success rates as shock wave lithotripsy for native small renal stones in children.

CONCLUSION

PDI is safe and effective for facilitating gravity-dependent drainage of renal stones and provides an opportunity to treat children in a quick, non-invasive, economic, painless, non-radiative and diverting fashion. This therapy is a valuable alternative in the pattern of stone management. In case of persistent fragments, it is recommend that the number of sessions be increased to six.

Outcome Analysis of Asymptomatic Lower Pole Stones in Children

PURPOSE

Lower pole renal stones in children usually present incidentally. To our knowledge frequency and need for intervention are unknown. We evaluated the outcomes of asymptomatic, incidentally found lower pole renal stones in children.

MATERIALS AND METHODS

We retrospectively reviewed the charts and renal ultrasounds of children with lower pole stones seen during a period of 14 years. The unpaired t-test was used to determine factors that might predict the need for stone intervention, including size, growth rate, type of stone and underlying metabolic disease. The success rate of nonoperative management, defined by spontaneous passage or lack of growth in the absence of symptoms, was calculated.

RESULTS

A total of 224 children were found to have lower pole stones. Mean ± SD age at presentation was 95.2 ± 65.3 months. Of the patients 120 (53.6%) spontaneously passed stones. Of the stones 25% remained asymptomatic and did not grow with time. Intervention was performed in 48 children (21.4%). Stones originally managed conservatively that later required intervention were significantly larger at baseline than stones that did not require intervention through the end of followup (median 7 vs 5 mm, p <0.001) and those that grew with time (median stone size 8 mm at surgical intervention, p = 0.01).

CONCLUSIONS

Our data suggest that asymptomatic lower pole renal stones can be followed conservatively. Of the calculi 78.6% passed spontaneously or remained asymptomatic and did not grow. Median initial size greater than 7 mm and stone growth with time were significant risk factors that predicted the need for intervention.

Predictive factors and management of steinstrasse after shock wave lithotripsy in pediatric urolithiasis--a multivariate analysis study

OBJECTIVE

To define the predictive factors for the formation of steinstrasse (SS) after shock wave lithotripsy (SWL) and determine the treatment strategies for this complication in pediatric urolithiasis.

METHODS

We retrospectively reviewed the data of 341 renal units (RUs) treated with SWL for urolithiasis. The stone location, stone burden, auxiliary procedures, energy level, and number of shock waves were recorded. Statistical analysis was performed to detect the predictive factors for the formation of SS. In addition, the treatment of children with SS was evaluated.

RESULTS

The mean age of the children was 8.31 years (range 1-17). Episodes of SS developed in 26 RUs (7.6%). Of the 26 RUs, 20 (77%) were localized in the lower, 5 (19%) in the upper, and 1 (4%) in multiple locations in the ureter. The stone burden was the only statistically significant factor predicting the formation of SS on logistic regression analysis (P = .001). Of the 26 RUs, 17 (65.4%) were successfully managed by repeat SWL monotherapy, 4 (15.4%) were managed with ureteroscopy after failure of SWL, 1 (3.8%) was managed by ureteroscopy monotherapy, and 4 (15.4%) were monitored with conservative management with antispasmodic drug plus hydration therapy. The mean number of SWL sessions was 1.72.

CONCLUSION

The incidence of SS development in children after SWL treatment was similar to that in adult series. Our results suggest that the stone burden is a significant predictive factor for the development of SS after SWL in pediatric urolithiasis. Most children with SS could be easily and safely treated by repeat SWL.

Extracorporeal shockwave lithotripsy vs. percutaneous nephrolithotomy vs. flexible ureterorenoscopy for lower-pole stones

Objectives

To review previous reports and discuss current trends in extracorporeal shockwave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL) and ureterorenoscopy (URS). ESWL was recommended as the first-line treatment for small and intermediate-sized stones in the lower pole, while it is the standard treatment for large stones. However, the stone clearance rate after ESWL seems to be lower than that of stones in other locations. This seems to result from a lower rate of fragment passage, due to anatomical factors.

Methods

Reports on urinary stone disease were reviewed, assessing only publications in peer-reviewed, Medline-listed journals in the English language (publication years 1990–2011).

Results

Recent experience with flexible URS (fURS) for intrarenal stones showed that excellent stone-free rates can be achieved. With increasing experience and technically improved equipment, fURS has become an alternative to ESWL for small and intermediate-sized renal stones. Furthermore, several authors reported successful retrograde treatment for large renal stones, proposing fURS as an alternative to PCNL. However, the major drawbacks are long operating times and commonly, staged procedures, which is why PCNL remains the method of choice for such stones.

Conclusions

Considering the currents trends and evidence, the 2012 update of the European Association of Urology Guidelines on Urolithiasis has upgraded the endourological treatment of kidney stones. Individual factors such as body habitus, renal anatomy, costs and patient preference must be considered.

SWL in lower calyceal calculi: evaluation of the treatment results in children and adults

OBJECTIVE

To evaluate the treatment parameters of shockwave lithotripsy (SWL) in lower calyceal calculi in adults and children in a comparative manner.

MATERIAL AND METHODS

Between 2006 and 2011, SWL was performed for lower calyceal calculi in 282 adults (mean age 48.5 years, range 28-64) and 54 children (mean age 48 months, range 5-141). The Wolf Piezolith 3000 lithotriptor has been used for SWL. Success rates, auxiliary procedures, additional interventions, and complications were evaluated in detail in a comparative manner.

RESULTS

Mean stone size was 7.7 mm (range 5-25) and 8.1 mm (range 5-23) in children and in adults, respectively. Mean SWL sessions were 1.5 (range 1-5) in children and 2.4 (range 1-6) in adults. Although 66.6% of children were stone-free after the first session, 28% of adult patients were stone-free after the first SWL session, showing a statistically significant difference (P = .0001). After the treatments, although a complete stone-free status was obtained in 85% of children, 31.5% of adults were stone-free at 3-month follow-up after SWL (P = .0001). Although no auxiliary procedures were needed in children, 8.2% of adults required them. Likewise, the percentage of additional procedures were higher in adults than children (20.2%).

CONCLUSION

SWL for lower calyceal calculi has been found to be highly successful in pediatric patients. These results demonstrate that, irrespective of stone size, SWL should be the first treatment alternative in the management of lower calyx stones in children.

Surgical management of pediatric urolithiasis

Pediatric urolithiasis poses a technical challenge to the urologist. A review of the recent literature on the subject was performed to highlight the various treatment modalities in the management of pediatric stones. A Medline search was used to identify manuscripts dealing with management options such as percutaneous nephrolithotomy, shock wave lithotripsy, ureteroscopy and cystolithotripsy in pediatric stone diseases. We also share our experience on the subject.

Shock wave lithotripsy should be the treatment modality for renal stone less than 1cm or < 150 mm² and proximal non-impacted ureteric stone less than 1 cm with normal renal function, no infection and favorable anatomy. Indications for PCNL in children are large burden stone more than 2cm or more than 150mm² with or without hydronephrosis, urosepsis and renal insufficiency, more than 1cm impacted upper ureteric stone, failure of SWL and significant volume of residual stones after open surgery. Shock wave lithotripsy can be offered for more soft (< 900 HU on CT scan) renal stones between 1-2cm. Primary vesical stone more than 1cm can be tackled with percutaneous cystolithomy or open cystolithotomy. Open renal stone surgery can be done for renal stones with associated structural abnormalities, large burden infective and staghorn stones, large impacted proximal ureteric stone. The role of laparoscopic surgery for stone disease in children still needs to be explored.

Clinical practice: surgical approaches to urolithiasis in children

The incidence of urolithiasis in children is increasing. Adequate knowledge of treatment modalities and surgical options is therefore essential for every pediatrician. Surgical approaches to urolithiasis in children continue to evolve with advancements in technology and sophistication of current equipment and techniques. Perhaps the most significant development in new techniques is the advent of robotic-assisted laparoscopy. This review, for the general pediatrician, summarizes the most recent pediatric data and guidelines for surgical approaches to treatment of urolithiasis.

Evaluation of renal function in children undergoing extracorporeal shock wave lithotripsy

PURPOSE

The effect of extracorporeal shock wave lithotripsy on the growing kidneys of young children has always been a concern. We determined whether shock wave lithotripsy causes renal parenchymal scarring or affects glomerular filtration rate in children.

MATERIALS AND METHODS

This prospective study included 100 children with renal stones who presented to the shock wave lithotripsy unit at our institution between March 2005 and March 2008. A total of 28 children had multiple stones in the same kidney. All children with bilateral renal stones had 1 kidney cleared of stones by percutaneous nephrolithotomy before undergoing shock wave lithotripsy. A total of 138 stones were subjected to shock wave lithotripsy. All children underwent radionuclide scan of the renal parenchyma using dimercapto-succinic acid, and glomerular filtration rate was estimated using diethylenetriamine pentaacetic acid before extracorporeal shock wave lithotripsy and 6 months afterward. Children with renal scarring due to previous surgery or vesicoureteral reflux were excluded from the study. The number of shock wave lithotripsy sessions to achieve stone-free status and the dose of shock waves used were recorded for each patient.

RESULTS

No patient demonstrated renal parenchymal scarring on dimercapto-succinic acid scan or any statistically significant change in glomerular filtration rate on diethylenetriamine pentaacetic acid scan up to 6 months after shock wave lithotripsy.

CONCLUSIONS

Shock wave lithotripsy is a safe modality for treating renal calculous disease in children up to 16 years old, with no impact on long-term kidney function.

Contemporary surgical management of pediatric urolithiasis

With miniaturization of instruments and refinement of surgical technique, the management of pediatric stone disease has undergone a dramatic evolution. While shock wave lithotripsy (SWL) is still commonly used to treat upper tract calculi, the use of ureteroscopy (URS) has dramatically increased and is now the procedure of choice for upper tract stone burdens less than 1.5cm at centers with significant experience. Percutaneous nephrolithotomy (PCNL) has replaced open surgical techniques for the treatment of large stone burdens greater than 2cm, with efficacy and complication rates similar to the adult population. Large institutional series demonstrate comparable stone-free and complication rates with SWL, URS, and PCNL, but concerns remain with these techniques regarding renal development and damage to the pediatric urinary tract. Randomized controlled trials comparing the efficacy of SWL and URS for upper tract stone burdens are needed to reach consensus regarding the most effective primary treatment modality in children.

Pediatric urolithiasis: the current surgical management

Children represent about 1% of all patients with urolithiasis, but 100% of these children are considered high risk for recurrent stone formation, and it is crucial for them to receive a therapy that will render them stone free. In addition, a metabolic workup is necessary to ensure a tailored metaphylaxis to prevent or delay recurrence. The appropriate therapy depends on localization, size, and composition of the calculus, as well as on the anatomy of the urinary tract. In specialized centers, the whole range of extracorporeal shock-wave lithotripsy (ESWL), ureterorenoscopy (URS), and percutaneous nephrolithotomy (PCNL) are available for children, with the same efficiency and safety as in adults.

Pediatric stone disease

Urinary stone disease is less common in children than adults. Although many aspects of pediatric stone disease are similar to that of adults, there are unique concerns regarding the presentation, diagnosis, and management of stone disease in children. We present a review of the increasing prevalence of pediatric stone disease, the diagnostic concerns specific to children, recent results from pediatric series regarding the expectant management and surgical treatment of stones, metabolic evaluation, and current research on the genetics of nephrolithiasis.

Shockwave lithotripsy and endourological management of urinary calculi in children: a single-center 10-year experience

PURPOSE

Shock wave lithotripsy (SWL) and endourological techniques revolutionized the management of pediatric urolithiasis. We sought to assess the impact of new technology and local practice in the treatment of pediatric urolithiasis during a 10-year period.

MATERIALS AND METHODS

Between 1997 and 2006, 125 children (90 boys and 35 girls), aged 18 months to 15 years, were managed in our department for urolithiasis. Stone localization, stone composition, presence of anatomic abnormalities, and treatment modality were evaluated retrospectively.

RESULTS

In 102 children, the stone was located in renal pelvis (0.5-45-mm diameter), in eight in the renal pelvis and one in the calyx; three had staghorn calculi; and 12 had ureteral stone (4-12-mm diameter). Ninety-three of 125 children underwent a total of 108 SWL sessions. Stone size ranged from 0.5 to 35 mm. The stone-free rates were 86%, 92%, and 96% after first, second, and third SWL session, respectively. Ureteroscopy was performed in 12/125 children, and 10/12 (83.5%) were rendered stone free. Nine of 125 children underwent percutaneous nephrolithotomy, and four of nine were stone free (44.5%), although five of the nine children (55.5%) required SWL for residual stone fragments. Open surgery was performed as initial procedure in 11 (9%) children. In 9 of 11 children, ureteropelvic junction obstruction was corrected simultaneously. Open surgery was followed by SWL in 3 of 11 patients. Two of three patients with staghorn calculi underwent nephrolithotomy and SWL and one of three with cysteinuria was managed with SWL.

CONCLUSIONS

SWL and endourological techniques are safe and effective in managing urolithiasis in pediatric patients. These minimally invasive methods reduced dramatically the cases of open surgery, which should be undertaken mainly in coexisting anatomic abnormalities.

Endourological management of pediatric stone disease: present status

PURPOSE

The incidence of nephrolithiasis in the pediatric population has been steadily increasing. The miniaturization of endoscopic instruments and improvement in imaging modalities have facilitated safe and effective endourological treatment in this patient population. We reviewed the current status of pediatric stone disease management.

MATERIALS AND METHODS

A comprehensive literature review was performed using MEDLINE/PubMed to evaluate the indications, techniques, complications and efficacy of endourological stone management in children.

RESULTS

In the 1980s shock wave lithotripsy revolutionized stone management in children, becoming the procedure of choice for treating upper tract calculi less than 1.5 cm. Percutaneous nephrolithotomy has replaced open surgical techniques for the treatment of stone burdens greater than 1.5 cm with efficacy and complication rates mirroring those in the adult population. However, at an increasing number of centers ureteroscopy is now being performed in cases that previously would have been treated with shock wave lithotripsy or percutaneous nephrolithotomy. Results from recent retrospective series demonstrate that stone-free rates and complication rates with ureteroscopy are comparable to percutaneous nephrolithotomy and shock wave lithotripsy. Although concerns remain with all endoscopic techniques in children regarding damage to the urinary tract and renal development, neither short-term nor long-term adverse effects have been consistently reported.

CONCLUSIONS

Shock wave lithotripsy, percutaneous nephrolithotomy and ureteroscopy are highly effective endourological techniques to treat stone disease in the pediatric population. A lack of prospective randomized trials comparing treatment modalities coupled with a vast disparity in the access to resources worldwide continues to individualize rather than standardize stone treatment in children.

Pediatric ureteroscopic management of intrarenal calculi

PURPOSE

Data addressing ureteroscopic management of intrarenal calculi in prepubertal children are limited. We reviewed our experience from January 2002 through December 2007.

MATERIALS AND METHODS

We retrospectively reviewed ureteroscopic procedures for intrarenal calculi in children younger than 14 years. Stone-free status was determined with postoperative imaging. Multiple logistic regression analysis was used to assess the influence of preoperative factors on initial stone-free status and the need for additional procedures.

RESULTS

Intrarenal calculi were managed ureteroscopically in 52 kidneys in 50 children with a mean age of 7.9 years (range 1.2 to 13.6). Mean stone size was 8 mm (range 1 to 16). Stone-free rate after a single ureteroscopic procedure was 50% (25 of 50 patients) on initial postoperative imaging and 58% (29 of 50) with extended followup. Initial stone-free status was dependent on preoperative stone size (p = 0.005) but not stone location. Additional stone procedures were required in 18 upper tracts. Younger patient age (p = 0.04) and larger preoperative stone size (p = 0.002) were associated with the need for additional procedures. Additional procedures were required in more than half of the stones 6 mm or larger but in no stone smaller than 6 mm.

CONCLUSIONS

Ureteroscopy is a safe method for the treatment of intrarenal calculi in the prepubertal population. Our ureteroscopic stone-free rate for intrarenal stones is lower than that reported for ureteral stones. Parents should be informed that additional procedures will likely be required, especially in younger patients and those with stones larger than 6 mm.

Is extracorporeal shock wave lithotripsy in pediatrics a safe procedure?

Removal of urinary calculi is an essential element in the successful treatment of patients with urinary stone disease. The new generation of lithotriptors allows the treatment without the need for general anesthesia. The patients, often outpatients, have a faster discharge from the hospital with a reduction of hospitalization time and operating costs. Shock wave lithotripsy (SWL) is currently considered a safe technique for treatment of pediatric urinary lithiasias, with a low percentage of complications and subsequent surgical retreatments. But can we define SWL as a safe procedure in pediatrics? Herein, we will review the literature to justify SWL safety in children, focusing on important parameters as the insertion of preoperative stenting, side effects, and complications after the procedure.

Ureteroscopic management of lower-pole stones in a pediatric population

PURPOSE

We report our experience with ureteroscopy to treat lower-pole calculi in children.

PATIENTS AND METHODS

A retrospective review was conducted of all ureteroscopic procedures for lower-pole stone disease at a pediatric institution from 2000 through 2005. A total of 13 girls and 8 boys with a mean age of 15 years (range 1-20 years) underwent flexible ureteroscopy for lower-pole calculi. The mean stone burden was 12 mm. Stone-free status was defined by postoperative abdominal radiography, CT, or ultrasonography.

RESULTS

Ureteral stenting was performed preoperatively in 38% and postoperatively in 71% of the patients. Ureteral-access sheaths were placed in 43%. There were no intraoperative or postoperative complications. With a mean follow-up of 11 months, 76% of the children were stone-free. The success rate for stones <15 mm was 93% v 33% for stones > or =15 mm (P = 0.01).

CONCLUSION

Ureteroscopy and laser lithotripsy are safe and effective in children with lower-pole calculi. Ureteroscopy can be considered a primary treatment option for children with lower-pole calculi <15 mm.

Is ureteroscopy first line treatment for pediatric stone disease?

PURPOSE

We report our current outcomes for ureteroscopic management of pediatric stone disease.

MATERIALS AND METHODS

We carried out a retrospective review of all ureteroscopic procedures for kidney or ureteral calculi performed between 2001 and 2005. Stone location and size, preoperative and postoperative stenting, intraoperative dilation, use of ureteral access sheath, stone-free rates and complications were noted.

RESULTS

A total of 100 patients (58% female, mean age 13.2 years) underwent 115 procedures. Stones were located in the renal pelvis in 6% of patients, upper pole in 10%, mid ureter in 11%, lower pole in 17%, proximal ureter in 19% and distal ureter in 37%. Mean stone size was 8.3 mm (median 7.0), with a mean of 1.5 stones per patient. Preoperative stenting was used in 54% of patients, and a stent was placed postoperatively in 76%. Ureteral coaxial dilators and ureteral access sheaths were used in 70% and 24% of patients, respectively. There were no major intraoperative complications, although 5 patients required stent placement for ureteral perforation or extravasation. One patient had a ureteral stricture requiring ureteral reimplantation. Mean followup was 10.1 months (median 2.6). Stone-free rate was 91% on followup ultrasound, abdominal radiography or computerized tomography. Seven patients required staged ureteroscopic procedures to achieve stone-free status. While the number of percutaneous nephrolithotomy and shock wave lithotripsy cases remained stable, the number of ureteroscopic cases increased 7-fold during this period.

CONCLUSIONS

Improved ureteroscopic access to stones throughout the pediatric urinary tract and stone-free rates that are comparable to the adult population have led to the adoption of ureteroscopy as first line therapy in children at our institution.

The impact of pelvicaliceal features on problematic lower pole stone clearance in different age groups

AIM

Our aim was to evaluate the impact of pelvicaliceal variables in pediatric and adult age groups who underwent SWL for lower caliceal calculi.

METHODS

25 pediatric and 78 adult patients treated with extracorporeal shock wave lithotripsy (SWL) between 1996 and 2004 were enrolled into the study after exclusion of patients with hydronephrosis, major renal anatomic anomalies, non-calcium stones, history of recurrent stone disease and previous renal surgery. Lower pole infundibulopelvic angle (IPA), infundibular length (IL), infundibular width (IW) and pelvicaliceal volume were measured from pre-SWL intravenous urography. The pelvicaliceal stone load (PSL) index implicating the stone burden of each patient described as the relationship between stone volume and total estimated pelvicaliceal volume for stone-bearing kidney was also calculated.

RESULTS

Sixty-eight percent of adult and 80% of pediatric patients became stone-free after SWL. The statistical insignificance between PSL index (p=0.097) of two groups shows that both groups shared a similar stone burden. According to SWL outcome, mean IPA values of stone-free and residual patients were 46.85 degrees and 30 degrees in pediatric group, respectively (p=0.01), whereas these values were 48.08 degrees and 43.06 degrees in the adult group, respectively (p=0.352). In the pediatric age group, stone-free and cumulative success rates increased with increasing IPA but this correlation was statistically insignificant (p: 0.263).

CONCLUSIONS

Lower caliceal anatomy has a higher impact on stone clearance after SWL in pediatric patients and urologists can expect better SWL outcomes from pediatric population with solitary lower caliceal stone than adults under the same conditions.

Pediatric shockwave lithotripsy: size matters!

BACKGROUND AND PURPOSE

Shockwave lithotripsy (SWL) is a safe and efficacious modality for pediatric urolithiasis. Recent reports claim good results even with larger stone burdens, irrespective of stone location. We reviewed the outcomes of SWL in the pediatric population at our center to assess the impact of stone burden and location and the age of the child on the stone-free rate.

PATIENTS AND METHODS

Records of 106 patients <or=16 years of age (mean age 10.9 years) treated with SWL for stones with a surface area of 20 to 600 mm2 (mean 124.17 mm2) from July 1989 to June 2004 were reviewed. Metabolic abnormalities were present in 20.7% of the patients. All procedures were performed using the Siemens Lithostar, and stone clearance was assessed 3 months after SWL. Complications and the need for re-treatment and ancillary procedures were noted, and the impacts of stone size and location and the age of the child on stone clearance were assessed.

RESULTS

The overall stone-free rate was 87% (complete clearance 72%; insignificant [<3-mm] residual fragments 15%). The re-treatment rate was 58%, and the efficiency quotient was 47. Whereas stone size correlated strongly with the stone-free rate (Mann-Whitney U test x = 0.004; chi-square test P = 0.02), patient age and stone location did not have a significant impact.

CONCLUSIONS

Extracorporeal shockwave lithotripsy is an effective modality to treat pediatric upper urinary-tract calculi, especially when the stone burden is <200 mm2. Larger stone burdens are associated with poorer results, necessitate more ancillary procedures, and have a higher complication rate.

Management of pediatric stone disease

Pediatric and adult stone disease differs in both presentation and treatment. Children can present with a wide range of symptoms varying from flank pain and hematuria to nonspecific symptoms such as irritability and nausea. Although ultrasonography and plain radiographs can play a role in diagnosis and follow-up, the standard of care for a child who presents to the emergency department with a history suggestive of a stone is noncontrast spiral CT. Because there is a high yield in identifying predisposing factors in children with urolithiasis and high recurrence rates, metabolic evaluation of every child with a urinary stone should be undertaken and medical treatment should be given if necessary. With recent advances in technology, stone management has changed from an open surgical approach to less invasive procedures such as extracorporeal shock-wave lithotripsy and endoscopic techniques. Herein, we present a review of the recent literature and offer our own preferences to approaches for treatment.

Factors affecting the success rate of extracorporeal shock wave lithotripsy for renal calculi in children

The aim of the study was to analyse factors affecting the success rate of extracorporeal shock wave lithotripsy (ESWL) in children with renal calculi. We performed a retrospective analysis reviewing records of 85 (40 female, 45 male) children (89 renal units) subjected to ESWL for treatment of renal calculi during 1990-2005 in our department. As 4 patients had bilateral calculi and 19 children (21 renal units) had renal stones at more than one different site, each location was analysed separately for convenience. The mean age of the patients was 10.3+/-4.6 (2-16) years. The stone-free rates for renal pelvis, lower, middle and upper caliceal calculi were 70, 62, 50 and 73%, respectively. A higher rate (33%) of insignificant fragments (< or = 4 mm) was noted for lower pole calculi. Increased stone diameter (P=0.0001) and burden (P=0.04) were found as the most significant factors that adversely affect the stone-free rate for pelvis renalis calculi, whereas an acutely oriented infundibulum and/or a long lower infundibulum (P=0.005) were unfavourable factors for clearance of lower caliceal stones. The stone-free rate in children with multiple calculi was 48%, while 29% of the renal units had retained fragments. ESWL is a good initial option for treatment of most of the renal calculi < 2 cm except in the presence of unfavourable lower caliceal anatomy. Increased stone burden, multiple stones, staghorn calculi, narrow lower infundibulopelvic angle and long lower infundibulum are factors that adversely affect the clearance rate.

Efficacy of extracorporeal shock wave lithotripsy for isolated lower caliceal stones in children compared with stones in other renal locations

OBJECTIVES

To evaluate the efficacy of extracorporeal shock wave lithotripsy (ESWL) monotherapy for isolated lower caliceal calculi in a pediatric age group and compare it with that for isolated middle/upper caliceal and renal pelvic calculi.

METHODS

We retrospectively reviewed the data of 151 renal units in 126 children treated with ESWL for isolated caliceal and renal pelvic stones from March 1992 to February 2004. The stones were localized in the lower, middle/upper calices, and renal pelvis in 50, 26, and 75 renal units, respectively. The results were compared with respect to renal location and stone burden.

RESULTS

The median patient age was 8 years (range 1 to 16). The median stone burden in the lower and middle/upper caliceal groups was significantly lower than in the renal pelvis group at 0.6, 0.6, and 1 cm2, respectively (P = 0.002). The overall stone-free rate was 62% for lower calices, 65.3% for middle/upper calices, and 80% for renal pelvis stones. For the group with a stone size greater than 2 cm2, the stone-free rate decreased to 33% in both lower and middle/upper calices; however, it was almost the same in the renal pelvis (81.8%). A highly significant relation was found between the stone burden and number of sessions (P < 0.001), but none between the stone burden and stone-free rate.

CONCLUSIONS

In our study, ESWL was equally effective for stones in all locations. We recommend ESWL as the primary treatment of choice for stones less than 2.0 cm2 in all caliceal locations. For the management of caliceal stones greater than 2.0 cm2, prospective randomized trials comparing ESWL and percutaneous nephrolithotomy are necessary.

Endoscopic management of stones in children

PURPOSE OF REVIEW

Management of pediatric urolithiasis has evolved from open surgery to minimally invasive techniques. With advancements in instrumentation, endourological procedures are being performed more commonly in children. The current article reviews the literature published from January 2003 to September 2004 regarding endoscopic management of stones in children.

RECENT FINDINGS

Whereas recent literature supports shock-wave lithotripsy as the preferred treatment option for pediatric stones, it also confirms the safety of percutaneous nephrolithotomy and ureteroscopy in all age groups. Retrograde intrarenal surgery and laparoscopic surgery are newer additions to the armamentarium of the endourologist but their role needs to be better defined.

SUMMARY

The majority of stones in children can be managed using minimally invasive techniques. Proper treatment planning and use of appropriate instrumentation are important to achieve optimal outcome.

Pelvi-calyceal height, a predictor of success when treating lower pole stones with extracorporeal shockwave lithotripsy

Extra corporeal shockwave lithotripsy (ESWL) is the treatment of choice for the majority of renal stones, however, it has the lowest success rate in complete clearance of stones located in the lower pole. We assess whether pelvi-calyceal height is a useful measurement in predicting successful stone clearance from the lower pole. A total of 105 patients with a solitary lower pole calculus of less than 20 mm treated with ESWL were reviewed. Stone size, location and pelvi-calyceal height were measured by intravenous urogram. Success was defined as complete stone clearance. Fifty-four patients (51.4%) had successful treatments, with the remaining 51 (48.6%) having incomplete stone clearance (including two patients in whom treatment had no effect). There was a statistically significant difference (P<0.0001) in pelvi-calyceal height between the two groups. Mean pelvi-calyceal height in patients with complete stone clearance was 15.1 mm (SD=3.9) compared with 22.9 mm (SD=5.2) for those with incomplete clearance. Pelvi-calyceal height is a useful predictor of success when treating lower pole renal stones with ESWL.